A new type of wearable sensor teeming with nanoparticles can help diagnose and treat movement disorders by storing and transmitting motion data and then delivering drugs when appropriate.
Sensors on skin -- which go by a range of names including epidermal electronics, flexible electronics, electronic tattoos) -- have long promised to record physiological measurements to help track health and monitor healing. This new wearable design, however, is multifuncational.
Developed by Dae-Hyeong Kim of Seoul National University and colleagues, it not only records and monitors health parameters, but it also stores the data locally and releases drugs as needed -- a first for any electronic skin system.
To help perform diagnostic and therapeutic tasks, the thin devices integrates stretchable sensors, memory, and actuators, and they’re all made of nanomaterials: silicon nanomembranes for motion sensing, gold nanoparticles for RAM data storage, and silica nanoparticles loaded with drugs within the thermal actuator, or microheater. All these tiny, tiny parts are layered into a soft patch -- about 4 centimeters long, 2 centimeters wide and 0.003 millimeters thick -- that can stretch and bend with your skin.
Here’s how it works. The system measures and records muscle activity on the human wrist, which helps diagnose motion-related neurological disorders such as Parkinson’s or epilepsy. Then the recorded data trigger the release of therapeutic agents (contained in the silica nanoparticles) by means of the thermal actuator, which allows the drug to diffuse into the skin. To prevent burns to the skin, a temperature sensor (made of the silicon nanomembranes) monitors the skin temperature.
The key is the memory device. But as a trade-off, the whole thing only works if it’s connected to a power supply and data transmitter. While commercially available parts (such as lithium batteries and radio-frequency identification tags) can do the work, they’re too rigid for this soft-as-skin brand of electronic device, study coauthor Nanshu Lu of the University of Texas, Austin, tells Nature. They’ll need to find a way to make them compact and flexible before the device can be used on patients.
The work was published in Nature Nanotechnology this week.
Image: Donghee Son and Jongha Lee